In the small-scale and steep channels for irrigation or drainage on the mountainous areas, bottom intakes or bottom divisions are safer and more economical than other types of diverging facility. The hydraulic characteristic of that kind of structure has not been made clear, even though the detail of it would be necessary for reasonable design. In this study, the flow around a bottom intake is analyzed experimentally, and also theoretically as potential flow using the hodograph and conformal mapping. In the analysis, the position of the stagnation point that appears on the division side of the diverging corner is considered to be an important factor for the determination of diversion discharge. As a result, a method to estimate the diversion rate is developed.

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